Instagram is indeed a great app to edit and share images; however, it doesn’t allow random image size to be posted /shared. The images must be or will be cropped to a square format (ideally 650 by 650 pixels if you plan to do it by Photoshop). Cropping sometimes takes away the beauty of the images. So here’s a nice application which helps to resize photos making it best for Instagram sharing + many others (There are many in fact but this is the one we use and it’s free)
Here are the step wise instructions (for iphone users)
After the app is installed, open the app it should display as follows:
Pressing on Camera should give you the option of either taking an image or choose from the library
If chosen Library (that is selecting from the image gallery you have) you can select the image you want to share on Instagram (or others too) Additionally you can also make various edits on the photos.
Click on Share and select Instagram
The application will ask to open in Instagram; click on it.
Now the photo is resized on Instagram (normally a border is added on top or below if the image is not square) >> make necessary edits on the photos
Type in your Caption and Share!